👁 Autonomic Nervous System (ANS) and the Eye
The autonomic nervous system operates independently from conscious control, and it significantly affects ocular functions.
It consists of the sympathetic and parasympathetic divisions, each targeting pupil size and lens accommodation.
🧠 Sympathetic Nervous System ("Fight or Flight")
ReceptorLocationEffect
| α1 | Pupil dilator | Pupil dilation (mydriasis) |
| β2 | Ciliary muscle | Relaxation → distant focus |
➡ Prepares the eye for alertness and threat detection
💓 Parasympathetic Nervous System ("Rest & Digest")
ReceptorLocationEffect
| M3 | Pupil sphincter | Pupil constriction (miosis) |
| M3 | Ciliary muscle | Contraction → near focus |
📌 Near Reflex = ACM
- Accommodation
- Convergence
- Miosis
✅ Summary
SystemSummary Action
| Sympathetic | Dilated pupils + far vision |
| Parasympathetic | Constricted pupils + near vision |
➡ These principles directly relate to mechanisms of glaucoma medications, to be covered next.
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